The small-flowered catchfly, a sticky-stemmed variety of campion, with small pinkish-white flowers, was once common across Britain, but the species has declined dramatically in recent decades, disappearing from 70 per cent of its range, with small populations of the plant only now surviving in Wales and the south and west of England, mostly by the coast.
The declines are blamed on the rise of intensive farming techniques and increased use of herbicides.
Now, 20,000 catchfly seeds have been sown on plots in Devon at the headquarters of international animal welfare charity the Donkey Sanctuary, near Sidmouth.
Next spring, the donkeys will be walked over the seeded plots in a process known as “treading in”.
The animals’ hooves ridge and compact the earth, helping embed the seed into the ground and hopefully boosting the flower’s chances of germination.
The seeds have been sown on plots alongside other wildflowers and grains chosen to create a landscape which can support threatened farmland birds such as the skylark, yellowhammer and linnet.
Once widespread, skylarks are declining rapidly due to habitat loss; yellowhammers, traditionally regarded as farmland birds, are also dying out; and linnets, named after the linseeds they love to eat, are declining due to agricultural intensification.
Ruth Angell, ecology and conservation manager at the Donkey Sanctuary, said: “Increasing biodiversity is essential for an enriched and resilient environment which can support rare species as well as our resident herds of donkeys.
“Our donkeys will be able to enjoy a walk with our grooms and benefit from one-to-one time while they walk over the plots.”
She added: “Our team of conservation officers and volunteers work on a range of projects across our sanctuary sites, including woodland, hedge and grassland management, to improve habitat for both wildlife and donkeys.”
The effort to save the small-flowered catchfly is part of the British conservation charity Plantlife’s “Colour in the Margins” project, which works to support rare field plants across the country.
The project is part of a wider programme to save more than 20 threatened species from extinction and boost 200 more through 19 projects across England, with support from the National Lottery Heritage Fund.
Cath Shellswell, manager for the Colour in the Margins project at Plantlife, said: “We're incredibly grateful to partners like the Donkey Sanctuary who are helping these fantastically rare wildflowers come back from the brink of extinction by giving them a helping hand in one of their original regional strongholds.”
Additional reporting by PA